The present invention relates to a pipe arrangement with a fluid-carrying inner pipe and an outer pipe that surrounds the inner pipe, wherein spacers are arranged between the inner pipe and the outer pipe in such a way that a gap is formed between the inner pipe and the outer pipe, wherein the outer pipe is joined at its first axial end section in a material-bonded manner or cohesive manner to a first spacer, which is joined to the inner pipe in a material-bonded, and wherein the outer pipe is arranged at its second axial end section at least partially with a radial distance to a second spacer, which is joined to the inner pipe in a material-bonded manner.
Directional information, such as “axial” or “axially,”, “radial” or “radially,” and “peripheral,” is basically to be understood as referring to the axis of the pipe arrangement, unless otherwise indicated explicitly or implicitly from the context.
For double-walled pipe arrangements, which are exposed to large thermal loads, there exists the problem that an outer pipe, which serves as a heat shield, and an inner pipe, which, for example, carries a hot fluid, such as, for instance, a coolant or an oil, must be able to move in relation to each other in order, to be able to compensate for different thermal expansions.
In the case of such pipe arrangements in the field of gas turbines, it is known not to join the second axial end section of the outer pipe to the inner pipe or to the associated spacer, so that the second axial end section is arranged around the spacer or the inner pipe in a free manner. In gas turbines, mechanical vibrations arise in operation and are transmitted to such pipe arrangements. As a result of mechanical vibrations of this kind, in particular in combination with the thermal influences that lead to a relative axial movement between the inner pipe and the outer pipe, the second end section of the outer pipe strikes or rubs against the spacer or the inner pipe. This leads to a high wear at the second end section of the outer pipe and at the spacer or at the inner pipe.